Cooling device and vehicle battery assembly

ABSTRACT

The invention refers to a cooling device ( 10 ) for a vehicle battery with at least one coolant line ( 12 ) and at least one separate clamping element ( 14 ), which is made of an elastic material, for pressing the coolant line ( 12 ) directly up against a flat surface of the vehicle battery. The coolant line ( 12 ) is flat, with an essentially flat upper surface ( 13 ) for contact with the flat face of the vehicle battery. The invention also concerns a vehicle battery assembly ( 100 ) with a vehicle battery that contains multiple battery elements ( 102 ) and a cooling device ( 10 ) such as that mentioned above.

The invention relates to a cooling device for a vehicle battery plus avehicle battery assembly. The battery is specifically the power sourcefor an electrical or hybrid vehicle.

Prior art discloses cooling devices for vehicle batteries in which aheat transfer plate is provided that is in contact with a surface of thevehicle battery that is to be cooled. In turn, the heat transfer plateis cooled locally by a coolant line. A cooling device such as this isexpensive to make and the heat that has to be removed from the vehiclebattery has to be transferred from the vehicle battery to the thermaltransfer plate and then from the thermal transfer plate to the coolantlines and finally to the coolant itself, whereby there is a heat flowwithin the heat transfer plate due to the local configuration of thecoolant lines.

The aim of the invention is to provide a coolant device for a vehiclebattery that is simple to construct and provides good cooling capacity,plus a vehicle battery assembly using such a device.

This problem is solved by a cooling device for a vehicle battery inaccordance with the invention, in which the cooling device has at leastone coolant line and at least one separate clamping element, made of anelastic material, to press the coolant pipework directly up against aflat side of the vehicle battery. The coolant line is flat, designedwith an essentially flat upper surface for contact with the flat side ofthe vehicle battery. Preferably, the cross-section of the coolant lineshould have a width that is greater than its height. The construction ofthe cooling device is straightforward, because it is designed for a flatside of a vehicle battery and does not need to be adapted for anycomplex three-dimensional shape the vehicle battery may have. The heatis transferred directly from the flat side of the vehicle battery viathe wall of the coolant line and into the coolant. An intermediatethermal transfer element between the coolant line and the surfaces ofthe vehicle battery that are to be cooled is thus not needed.

The upper side of the coolant line is the side of the coolant line withthe broader cross-section.

Making the coolant line in a flat shape means on the one hand that theupper side for contact with the flat side of the vehicle battery becomeslarger, and on the other that the height of the space needed to buildthe cooling device in is reduced.

The upper side of the coolant line and cooling device is defined as thatside of the coolant line or cooling device that is in contact with theflat side of the battery. In particular when the coolant device has beenbuilt into a vehicle battery assembly, the directions should thereforebe seen as being relative to the flat side of the battery.

The flat side of the vehicle battery can refer to the entire vehiclebattery or to an individual battery cell group—so-called batterypacks—that for example contain battery cells connected together within acasing, or in the case where the vehicle battery has several batterypacks.

The coolant line may have a cross-section that is slightly convextowards the top when not pressed in place. The compressive force appliedby the clamping element presses the upper side of the flat coolant linefully flat against the flat side of the vehicle battery, thereby eveningout the manufacturing tolerances between the flat side of the vehiclebattery and the coolant line.

According to a preferred embodiment, the clamping element is placedagainst the underside of the flat coolant line, preferably at oppositeside edges of the coolant line.

It is possible for the clamping element to consist of two independentlydeformable arms, preferably angled obliquely upwards to the coolantline, each placed at opposite side edges at the underside of the flatcoolant line, with the coolant line preferably bridging the arms. Inparticular, the clamping element is made as a single piece.

The clamping element can be made in such a way that pressing theclamping element against the coolant line against the flat side of thevehicle battery with a predefined compressive force deforms the clampingelement elastically into a compressed configuration, instead of thebasic configuration in which the clamping element is not pressed upagainst the flat side of the battery.

To create the cooling device as a structural unit, for example for easeof transport, the clamping element can be created in a shape thatinterlocks with the coolant line.

For good thermal insulation of the coolant line and the vehicle battery,at least one thermal insulation component can be included that is boundto the clamping element and provides insulation for the flat side of thebattery.

Preferably, the clamping element is at least partially embedded in thethermal insulation component. This makes it easy for the clampingelement and the thermal insulation component to interlock with oneanother.

It is possible for the underside of the clamping element to beextensively (and more specifically completely) in contact with thethermal insulation component. To compensate for bending of the clampingelement or manufacturing tolerances, the thermal insulation componentcan be deformable and/or compressible. For example, the thermalinsulation component is at least partially deformed and/or compressedwhen the clamping element deforms.

The said one or more clamping elements and/or one or more thermalinsulation components can be made of plastic and a thermoplasticelastomer (TPE), in particular by two-component injection molding.

Multiple clamping elements can be used, mechanically connected via atleast one thermal insulation component. This makes is possible toposition the various clamping elements with respect to each other usingthe thermal insulation components to which the clamping elements arebound.

The one or more coolant lines, one or more clamping elements and one ormore thermal insulation components preferably define a cooling floor, ofwhich the total surface matches the flat side of the vehicle battery.The surface of the cooling floor thereby matches the area of the flatside of the vehicle battery pack that is to be cooled, or the entirebattery. In this way, the total surface area of the cooling floor isaligned to the surface of the vehicle battery pack that is to be cooled,or of the entire battery pack.

The upper surface of the upper sides of the coolant lines canadvantageously cover between 35% and 70% of the total surface of theflat side of the vehicle battery. This means that the upper surface ofthe upper sides of the coolant lines are aligned with between 35% and70% of the total surface area of the base of the battery that is to becooled. The improved heat transfer means that it is not necessary todesign the entire upper side of the cooling floor or the entire basesurface of the battery module as flat coolant lines.

The cross-section of the coolant line is for example twice as wide asits height, or preferably five times or even more preferably ten timesgreater. The flatter the design of the coolant line, the larger theupper side becomes and the lower the built-in height of the coolingdevice can therefore be.

The coolant line is for example a flat two-dimensional component,preferably with multiple parallel coolant channels.

The coolant used in the cooling device can be either a phase-changingrefrigerant fluid or a coolant liquid.

According to one preferred variant, multiple coolant lines are providednext to one another, wherein the coolant lines preferably have a commonthermal insulation component and the clamping elements are held in thethermal insulation component. If multiple coolant lines are used, largersurfaces are cooled and/or multiple coolant lines of lesser width can beused.

The aim of the invention is further achieved by using a vehicle batteryassembly with a vehicle battery that contains multiple battery elements,plus one of the above-mentioned cooling devices, wherein the coolingdevice is positioned between one of the flat sides of the batteryelements that are to be cooled and a casing of the vehicle battery, andat least one coolant line that is placed directly up against the flatsurface of the battery elements that are to be cooled.

Further characteristics and benefits of the invention derive from thedescription below and from the following drawings, to which reference ismade. The drawings show:

In FIG. 1, a cooling device according to the invention, in its basicconfiguration;

In FIG. 2, a cooling device according to FIG. 1, in the compressedconfiguration;

In FIG. 3, a cooling device according to a second variant of theinvention;

In FIG. 4, a vehicle battery assembly with a cooling device inaccordance with a third embodiment of the invention, and

In FIG. 5, a detailed view of the flat coolant lines of a cooling devicein accordance with FIG. 4.

FIG. 1 shows a cooling device 10 with a coolant line 12, a clampingelement 14 and two thermal insulation elements 16. The coolant line 12is flat, with the cross-section of the coolant line 12 being broaderthan it is high. In the variant shown, the breadth of the coolant line12 is more than ten times as great as its height.

The coolant line 12 is divided by several supporting walls 18 intonumerous coolant channels 20. These supporting walls 18 increase themechanical stability of the flat coolant line 12.

To reduce the weight of the cooling device 10, it is advantageous forthe strength of the wall of the coolant line 12 to be kept to a minimumand for the coolant line 12 to be made of a lightweight material such asaluminum, for example by extrusion.

The clamping element 14 has a flat bottom section 22, from which twoarms 24 extend diagonally upwards to the coolant line 12. At the ends ofthe arms 24, the clamping element 14 is located at opposite side edgeson the underside of the flat coolant line 12, with the coolant line 12bridging the two arms 24.

Furthermore, the arms 24 each have an extension 26 at their ends,enclosing the coolant line 12 at the side edge and thereby creating aninterlocking connection between the clamping element 14 and the coolantline 12.

The clamping element 14 is made of elastic material, so that it canpress the coolant line 12 directly up against a flat side of the vehiclebattery. FIG. 1 shows a basic configuration of the clamping element 14,in which the clamping element 14 is not pressing the coolant line 12 upagainst the flat side of the battery. In this basic configuration, theclamping element 14 can be elastically relaxed or can providepre-tensioning that acts on the extensions 26 of the clamping element 14against the side edges of the coolant line 12.

The thermal insulation components 16 are manufactured from a deformableand/or compressible foam material. The two thermal insulation components16 are each interlocked with and bound to the clamping element 14. Aprojection 28 of the clamping element 14 at the bottom section 22engages in the thermal insulation component 16. In the embodimentillustrated, parts of the clamping element 14 are embedded in thethermal insulation component 16.

In order to make it easier to deform the thermal insulation component16, deformation cut-aways 30 are made on the upper and lower sides ofthe thermal insulation component 16. These deformation recesses 30 canalso be used to achieve intended changes in local deformation behaviorof the thermal insulation component 16.

Coolant line 12, clamping element 14 and the thermal insulationcomponent 16 form an interconnected assembly, which is a cooling floor32.

FIG. 2 shows the cooling device from FIG. 1, wherein the cooling device10 has been built into a vehicle battery assembly 100 and positionedbetween a battery element 102 and the casing 104 of a vehicle battery.The height of the cooling device 10 has been compressed, in which thearms 24 of the clamping element 14 are elastically sprung in acompressing configuration and the upper side 13 of the coolant line 12is pressing against a flat side 103 of the battery element 102 with aspecific contact pressure.

Similarly, the thermal insulation components 16 are deformed,particularly in the area around the deformation cut-aways 30.

The contact force exerted on the coolant line 12 is determined on theone hand by the spring constants of the deformable arms 24 of theclamping element 14 and on the other by the compressibility of thematerial of the thermal insulation component 16, particularly in thearea around the clamping element 14.

As can be seen in FIG. 2, the extensions 26 of the arms 24 are no longerengaged with the side edges of the coolant line 12 when in the clampingconfiguration. When the clamping element 14 is relaxed, the arms 24 willhowever spring back and the extensions 26 will once again engage withthe side edges of the coolant line 12. This ensures that the coolantline 12 is permanently attached to the clamping element 14 when the unithas not been built in.

FIG. 3 shows a second embodiment of a cooling device 10, in which thethermal insulation component 16 is designed in such a way that there isno material of the thermal insulation component 16 at the bottom section22 of the clamping element 14. This makes it easier to deform theclamping element 14. The thermal insulation component 16 is interlockedwith a protrusion 28 of the clamping element 14 at the arms 24.Moreover, the clamping element 14 has a rough surface in the contactarea of the thermal insulation component 16, to achieve better adhesionbetween the thermal insulation component 16 and the clamping element 14.

FIG. 4 illustrates a third variant of the cooling device 10, whichcomprises a cooling floor 32 with two coolant lines 12, two clampingelements 14 and three thermal insulation components 16.

The coolant lines 12 and the clamping element 14 are all identical tothose in the cooling device 10 shown in FIGS. 1 and 2. The two clampingelements 14 are each interlocked with and bound to the central thermalinsulation component 16. The central thermal insulation component 16 isa common thermal insulation component 16 in which the clamping elements14 are lodged and which thereby defines the relative positioning of theclamping elements.

It is also possible for the three thermal insulation components 16 shownin FIG. 4 to be connected directly to each other.

The cooling floor 32 has a total area on the upper side that matches theflat side surfaces of the battery elements 102 that are to be cooled.The surface area of the upper side 13 of the coolant lines 12 comprisesbetween 35% and 70% of the total area of the top surface of the coolingfloor 32.

FIG. 5 shows a perspective view of the two coolant lines 12 of thecooling device from FIG. 4. The two flat coolant lines 12 each have acoolant connector 34 on their front faces. The first coolant line 12,which is shown at the bottom right of FIG. 5, has a first coolantconnector 34 that is connected to a coolant inflow 36, and an opposingsecond coolant connector 34 that is connected via a coolant loop 38 to acoolant connector 34 on the second coolant line 12. The second coolantconnector 34 of the second coolant line 12 is connected to a coolantoutflow 40.

The two coolant lines 12 are integrated into a common coolant circuit,in which the coolant lines 12 flow in opposite directions. It is ofcourse also possible for a coolant device 10 to have multiple coolantlines 12 that are integrated parallel to one another in a coolantcircuit.

A phase-changing coolant fluid or a coolant liquid can be used as therefrigerant. The coolant connections 34 permit a distribution of thecoolant over multiple coolant channels 20 in particular.

In the embodiments shown, the clamping element 14 is always made as asingle piece. It would however also be possible to make the clampingelement in several pieces, for instance using elastic and inelasticcomponents. It is also possible for the clamping element 14 to extendover the entire length of the coolant line or for several clampingelements 14 to be provided along the axial direction of the coolant line12.

The clamping element 14 and the thermal insulation element 16 are madeof a material with low thermal conductivity, to reduce heat conductionbetween the casing 104 and the flat side 103 of the battery element 102or the coolant line 12. The clamping element 14 and the thermalinsulation element 16 can be made together, for instance by casting ortwo-component injection molding.

In the variant shown, the two arms 24 of the clamping element 14 areeach up against opposite side edges of the coolant line 12.Alternatively, it is possible for the clamping element to be up againstthe entirety of the coolant line 12 and supported against the casing ofthe vehicle battery with two arms that extend diagonally downwards.

The battery elements 102 can be individual battery cells or battery cellassemblies, which for example are designed in a common housing with acommon electrical connection and common surfaces to be cooled.

The coolant line 12 is preferably made of a lightweight material withhigh thermal conductivity, especially aluminum, which in the illustratedembodiment is an extrusion profile.

The coolant lines 12 can have a slight convex bulge upwards when theyare not pressed against the bottom of the battery (see the dashed linesin FIG. 1). This means that a tensioning force will be exerted upwardswhen a force is applied to the side edges, in order to even outtolerances and unevenness of the battery bottom and the upper side ofthe lines 12.

The coolant used can be either a single-phase coolant, for instancewater, glycol or a water/glycol mixture, or a phase-changingrefrigerant, particularly based on carbon dioxide.

1. A cooling device (10) for a vehicle battery with at least one coolantline and at least one separate element, which is made of an elasticmaterial, for pressing the coolant line directly up against a flatsurface of the vehicle battery, wherein the coolant line has anessentially flat upper surface for contact with the flat surface of thevehicle battery and the cross-section of the coolant line has a widththat is greater than its height.
 2. A cooling device according to claim1, wherein the coolant line has a cross-section that is convex in shapetowards an upper side when not pressed in place.
 3. A cooling deviceaccording to claim 1, the separate element is up against an underside ofthe coolant line.
 4. A cooling device according to claim 1, wherein theseparate element comprises two independently deformable arms each placedat opposite side edges at an underside of the coolant line (12).
 5. Acooling device according to claim 1, wherein the separate element isshaped to interlock with the coolant line.
 6. A cooling device accordingto claim 1, wherein at least one thermal insulation component isincluded that is bound to the separate element and that providesinsulation for the flat surface of the battery.
 7. A cooling deviceaccording to claim 6, wherein the separate element is at least partiallyembedded in the thermal insulation component.
 8. A cooling device (10)according to claim 6, wherein the separate element is extensively incontact with the thermal insulation component.
 9. A cooling device (10)according to claim 1, wherein multiple separate elements are used,mechanically connected via at least one thermal insulation component.10. A cooling device according to claim 1, wherein the one or morecoolant lines, the one or more separate elements and one or more thermalinsulation components define a cooling floor, of which the total surfacecorresponds to the flat surface of the vehicle battery.
 11. A coolingdevice according to claim 1, wherein upper surfaces of upper sides ofthe coolant lines are aligned with between 35% and 70% of the totalsurface area of the base of the battery that is to be cooled.
 12. Acooling device according to claim 1, wherein a cross-section of thecoolant line is twice as wide as it is high.
 13. A cooling deviceaccording to claim 1, wherein the coolant line is a flat,two-dimensional component having multiple coolant channels.
 14. Acooling device according claim 1, wherein multiple coolant lines areprovided next to one another, and wherein the coolant lines have acommon thermal insulation component and the separate elements are heldin the thermal insulation component.
 15. A vehicle battery assembly witha vehicle battery containing multiple battery elements having flat sidesand a cooling device according to claim 1, wherein the cooling device ispositioned between one of the flat sides of the battery elements thatare to be cooled and a casing of the vehicle battery and at least onecoolant line that is placed directly up against the flat side (103) ofthe battery elements that are to be cooled.
 16. A cooling deviceaccording to claim 1, wherein the separate element is a holding element.17. A cooling device according to claim 1, wherein the separate elementis a support element.